Title:Airborne inhalable metals in Commercial, Residential and Industrial areas of Karachi,
Pakistan: Distribution, Source Apportionment and Health Risks
Short Running Title:Airborne inhalable metals in Karachi and Health Risks
Durdana Rais Hashmi*, Akhtar Shareef, Farooq Ahmed Khan
and Alia Bano Munshi
Centre for Environmental Studies PCSIR Labs Complex, Karachi
Abstract
Air pollution especially Air borne particulate matter is becoming a major problem in Karachi
city. This study was aimed to determine the concentration of trace metals present in air borne
particulate matter. The samples were collected from 108 locations categorized as Commercial,
Residential, Industrial and Urban background zones of Karachi. The samples were digested using
acid digestion method and atomic absorption spectrophotometer was used for the elemental
analysis. The samples were analyzed in collected particulate matter (PM10) for trace metals, lead
(Pb) and cadmium (Cd). The maximum average concentration of Pb were found in commercial
zone 1.36 µg/m3, in Residential zone 0.92 µg/m3, in Industrial zone 1.21 µg/m3 and in urban
background zone 0.08 µg/m3, whereas; Cd concentration in commercial zone 0.008 µg/m3, in
Residential zone 0.006 µg/m3, in Industrial zone 0.009 µg/m3 and in urban background zone
0.003µg/m3 respectively. Comparison with the results reported in other published studies shows
the difference in concentration on the basis of different activity in the selected zones.
Furthermore, health effects due to identified metals were also investigated and found hazardous
for human health.
Keywords: Trace Metals, Lead, Cadmium, Particulates Matter, AAS, Health Effect
Introduction
Environmental pollution is the presence of different harmful elements into certain environment
that gives make unhealthy to live in. Presence of different harmful elements into certain
environment beyond the permissible limits that gives unhealthy environment to live in Called
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pollutants e.g., Cd, Pb, Zn, Cu, Ni and Mn. These elements are released into the atmospheric air
from different natural and anthropogenic activities. High rate of urbanization, unplanned
industrial development, traffic congestion, indiscriminate use of pesticides and fertilizers are the
main factor responsible for trace metal pollution in ambient air environment. Periodic table
consisting of hundred and ten elements from which twenty two have been act as normal
constituents of biological tissues. While only 0.4% contributes as trace metals and found as toxic
or poisonous metals even at low concentrations (Duruibe, J.O., et al., 2007). However, it is
generally known that continuous ingestion of toxic metals even in low doses, lead to adverse
health effects and cause permanent damage on human health.
Trace metal concentration in particulate matter of air helps to evaluate the degree of atmospheric
pollution and health hazards to human population. The population in urban areas highly exposed
to the aerosol toxic metals. Several researches on atmospheric metal concentration and their
associated health hazards have been conducted in different parts of the world showing various
fluctuations and disparities in trace metal constituents. All these metals produce different
diseases like Lead and Cadmium causes slowing of heart rate, leukemia and different types of
cancer (Shahid A. T et al, 2013).
Due to the lack of appropriate air quality management capabilities, the Pakistan is suffering from
deterioration of air quality. Evidence from various governmental organizations and international
agencies has indicated that air pollution is a significant risk to the environment, quality of life
and human health.
Atmospheric aerosol particles are solid or liquid particles suspended in air. Processes that,
control formation, transformation and the removal of atmospheric aerosols is of great interest in
atmospheric science. Atmospheric particles show an imported role in atmospheric air. It may
persuade the visibility, environmental conditions and health hazards. In the atmospheric air,
presence of particulate matter, toxic metals and some other organic pollutants are considered as
priority pollutants by World Health Organization (WHO, 2000).
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The rapid unplanned industrialization, high rate of urbanization, traffic congestion and
haphazard’s use of pesticides in agriculture increases the level of toxic metals in the atmospheric
air. Emissions from the fossil fuel combustion, solid waste incineration, stacks of industries,
vehicular emissions and other human activities are chief sources of toxic metals metals, in urban
environment. Toxic metals produce hazardous effects on human health. Toxic metals like lead
and cadmium are toxic even at low levels (Itoh et al, 2006; Kalantari , 2008 and Vinodhini &
Narayanan, 2009]).
In recent years, most of the researches have focused on the concentration, distribution and
identification of toxic metals in the atmospheric particulate matter. Several researches on soil,
water and plants in Karachi city have detected high concentration of toxic metals in the
environment.
It has been estimated that urban air pollution causes ˜360 000 premature deaths each year in Asia
while an estimated 10 500 premature deaths occur per year in Delhi, India, due to toxic metal
pollution (Gurjar et al., 2010).
During last two decades, significance of this research lies in the risk pollutants and their impact
on the public health (Chirenje, T. et al.,2006, Inyang, H.I. and S. Bae, 2006). Exposure to toxic
metals in the atmospheric air can occur by means of ingestion, inhalation and dermal contact.
The adverse health effects of toxic metals in the atmosphere include respiratory infections,
asthma, premature deaths, cardiovascular diseases and risk of the cancer (Sicard.P, et al, 2011).
In Pakistan, air quality deteriorating continuously because the lack of air quality management
capabilities Indication about a significant risk to the environment, quality of life and human
health have been shown from various governmental organizations and international agencies
(Mavroidis I, Chaloulakou A; 2010).
The aim of present study was to investigate the concentration of trace metals (Pb, and Cd) at
different selected areas in Karachi city. These results were also compared with other similar
3
studies quoted in national and international journals having impact factors. It is hoped that this
study will be very useful towards the future environmental study programs.
Materials and Methods
Sampling
One hundred eight locations were selected for sample collection on the main roads, side road,
round about, and open places along the busy roads of Karachi (Figure - 1), and these locations
were categorized as commercial, residential, Industrial and urban Background zones of the
Karachi’s environment. Samples were collected using high volume air sampler for a period of 24
hrs (1440 min) with an average flow rate of 1.0 m3/min. Samples on glass fiber filters were
collected with the collection efficiency of 95 %. Then using oxidizing acid mixture, wet
digestion of samples was performed and the digested samples were then analyzed by AAS for
trace elements Pb and Cd respectively.
Figure 1: Location map
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Reagents
All the experiments were performed with analytical reagent grade chemicals. All the glassware
were extensively soaked with diluted HNO3 and rinsed twice with distilled water. The reagents
were ultra pure or analytical (A.R) grade and diluted by distilled and de-ionized water. Reference
standards were prepared from ACCU (Traceability of these standards to National Institute of
Standards and Technology) standard (1000 mg/lit).
Sample Preparation:
Particulate matter Samples were collected on glass fiber filters. The digested samples were
dissolved in an acid mixture containing 10 ml of 65% HNO3 and 4 ml of 60% HClO4. Organic
matters were decomposed and metal ions were changed into their respective nitrates. The
mixture is then filtered through No.42 Whatman filter paper into a volumetric flask and made up
to the mark by adding de-ionized water.
Apparatus
Analysis was performed on AAS (Hitachi Z- 8000), with Zeeman Effect background correction.
The Spectrophotometer is outfitted with a graphite furnace, a microprocessor and a built in
printer. Determination of trace metals (Pb & Cd) was carried out by Electro-thermal Atomic
Absorption Spectrometry (ETAAS) on AAS, employing the standard addition technique.
Measurement was made by using the hollow cathode lamp for the metals Pb and Cd respectively.
Analysis of Soil Samples
Sample of particulate matter analyzed for Pb and Cd with elector-thermal ETAAS. Triplicate
readings were taken on each sample by AAS, and the mean values of these readings were used to
calculate results. The working conditions for detected elements by AAS are presented in Table 1.
Table – 1 : Working Condition for Detected Elements by Atomic Absorption Spectrophotometer.
Parameters
Slit (nm)
Wave length (nm)
Drying temperature (°C)
Ashing Temperature (°C)
Atomization Temperature (°C)
5
Pb
1.3
283.3
80 - 120
400
2000
Cd
1.3
228.8
80 - 120
300
1500
Results and Discussion
One hundred eight (54+36+14+4) samples of particulate matter were collected from the main
roads, side road, round about, and open places along the busy roads of Karachi (Figure 1), and
these locations were categorized as commercial (54 locations), residential (36 locations),
Industrial (14 locations) and urban Background zones (04 locations) of the Karachi city. Analysis
of these particulate matter samples were carried out for Lead and Cadmium respectively, by
using Atomic Absorption Spectroscopy (AAS) employing standard addition method. The
average concentration of Lead and Cadmium for commercial (54 locations), residential (36
locations), Industrial (14 locations) and urban Background zones (04 locations) are presented in
Figure 2, 3, 4 and 5. The level of investigated Lead and Cadmium in particulate matter (PM10)
samples was found in µg/m3.
Figure-2-5 shows the average concentration of lead and cadmium in commercial, residential,
Industrial and urban Background areas of Karachi city during the year of 2009-2011.
Figure-2 shows the concentration of lead and cadmium at 54 locations in Commercial areas of
Karachi. Maximum average concentration of lead and cadmium found at location C-46 (3.5
µg/m3 Pb) and (0.019 µg/m3 Cd) respectively. The high concentration of lead and cadmium may
be due to the large parking place for hundreds of vehicles near this round about with very high
traffic density. Moreover; the roads are narrow and congested with high traffic density. The
lowest concentration of lead and cadmium in commercial areas was found at location C-6 (0.21
µg/m3 Pb) and (0.002 µg/m3Cd) respectively. The low concentration at this location may be
because this is an open place on wide road having low traffic density with low emissions. All the
sampling points in commercial areas were on the busiest intersections in Karachi and are
surrounded by multistoried buildings both for commercial offices and residential buildings on
main roads and round about having high traffic density.
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Figure – 2
Concentration of Trace Metals (Pb and Cd) in Commercial Areas of Karachi city
Figure 3 shows the concentration of lead and cadmium at 36 locations in residential areas of
Karachi. Maximum concentration of lead and cadmium found at location R-31 (3.1 µg/m3 Pb)
and (0.024µg/m3 Cd) respectively. The factors responsible for high values at R-31 are
multistoried buildings located at both side of the roads which produce tunnel effect in this area
and high traffic density, whereas, the lowest concentration of lead and cadmium found at
location R-3 (0.27µg/m3 Pb) and (0.002 µg/m3 Cd) respectively due to open place with low
vehicular emissions. Residential areas covered with densely populated areas having high traffic
density. The sampling points in residential areas are also covered with the busiest intersections in
Karachi and surrounded by single and mostly multistoried buildings for residence. The
populations living around the selected locations were middle and high income group and also
have high emission of vehicles.
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Figure -3
Concentration of Trace Metals (Pb and Cd) in Residential Areas of Karachi city
Figure 4 shows the concentration of lead and cadmium at 14 locations in industrial areas of
Karachi. Maximum concentration of lead and cadmium found at location I-14 (2.34 µg/m3 Pb)
and (0.020 µg/m3 Cd) respectively. Increase in trace metal pollution at this location may be due
to high traffic density and emission from the industries which are located on main roads of the
city. Whereas; lowest concentrations of lead and cadmium found at location 1-2 (0.17 µg/m3 Pb)
and (0.002 µg/m3 Cd) respectively, the low values found here may be because these industrial
areas has relatively open place and situated on the intersection of very wide road. The sampling
points in industrial areas having different types of industries. The areas covered SITE, LITE,
KIA and Port Qasim. Approximately 60 percent of the industries are textile mills, while other
involve pharmaceuticals, chemicals, detergents, iron and steel, Sulphur refining, vegetable oil,
beverages and food products.
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Figure -4
Concentration of Trace Metals (Pb and Cd) in Industrial Areas of Karachi city
Figure 5 shows lead and cadmium concentration at 04 locations in background areas of Karachi.
Maximum concentration lead and cadmium in urban background areas was found at location Ub-2 (0.12 µg/m3 Pb) and (0.005µg/m3 Cd), whereas minimum concentration was found at
location u-b-4 (0.06 µg/m3 Pb) and (0.002µg/m3 Cd) respectively. The low values found here
may because the locations selected in urban background areas are relatively open places and
situated on wide roads having low traffic density. The sampling points ub-2 and ub-3 in Urban
background areas are 390 Km away from the main super highway whereas ub-1 and ub-4 are
situated on wide road. The areas around the sampling site are sparsely populated having low
vehicular traffic.
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Figure - 5
Concentration of Trace Metals (Pb and Cd) in Urban Background Areas of Karachi city
Lead has been found to be one of the major toxic elements generated through the motor vehicle
exhaust using leaded gasoline. It is non degraded pollutant and it not only accumulate in the
body but also modifies itself as it moves through biological cycles and food chain. The relatively
high lead concentration in Karachi could predominantly originate from burning of solid waste
and from large number of vehicles. Emission from road or wind-blown dust, or other industries
may also have significant contribution to the lead pollution in Karachi city. Previously, much
attention has been paid towards lead in the atmosphere due to wide spreads use as an antiknocking agent in gasoline (Jones, B. J., 1991). Presently, however, after the introduction of the
regulations requiring the reduction in the lead content in gasoline markedly decreased from 0.64
g/lit in 1966 to 0.14 g/lit in 1986, this decrease of lead concentration in gasoline also decrease
the addition of lead to the environment by using in the motor vehicles. Whereas, previously
deposited lead concentration in the environment is a main source of lead in present environment.
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Even though the concentration of lead decreases in the gasoline but due to increase of vehicles in
the city also increase the emission of lead in the environment of the city.
The average concentration of cadmium at some points exceeded the WHO guidelines value
(0.005 µg/m3) in commercial and industrial areas at selected points in Karachi. The higher
cadmium concentration in industrial areas of Karachi may be due to the release of cadmium from
different industrial and mechanical process. Whereas in commercial areas may be due to the
vehicular traffic. The sources of cadmium are diesel and lubricating motor oil, tyres and
galvanized part of the vehicles. Diesel oil contains 0.07 to 0.1 ppm of Cd, whereas lubricating oil
contains 0.26 ppm. The wear and tear of automobile tyres, which contain 20 – 90 ppm Cd, is
main source of Cd pollution (I.H Qureshi, 2000). However the cadmium concentration has the
lowest concentration than the measured concentration of lead in this study. Care should be taken
about the sources and remedy of the high level of cadmium pollution in Karachi as it has serious
impact on human health.
Table 2. Comparison of metal concentrations (µg m3) with other parts of the world
Location /Site
type
Typography
Cd
Pb
Reference
Commercial
0.008
1.36
Residential
0.006
0.92
Karachi, Pakistan
Present Study
Industrial
0.009
1.21
U-background
0.003
0.08
background
Residential
Delhi, India,
0.01-0.02 0.27-0.46 Khillare and Sarkar, (2012) [15]
Residential
Coimbatore, India
BDL
0.21-0.62 Vijayanand et al., (2008) [16]
Urban
Agra, India
NR
1.1
Kulshrestha et al., (2009) [17]
Urban
Delhi,lndia
0.01
0.44
Shridhar et al., (2010) [18]
Urban
Lahore, Pakistan
0.08
4.4
von Schneidemesser et al., (2010) [19]
Residential
Beijing, China
0.005
0.33
Khan et al., (2010) [20]
Residential
Tocopilla, Chile
NR
0.01
Jorquera, (2009)a [21]
Urban
Istanbul, Turkey
0.001
0.07
Theodosi et al., (2010) [22]
Lecce, ltaly
Urban background
NR
0.008
Contini et al., (2010) [23]
Urban
Vienna, Austria
0.0005
0.01
Limbeck et al., (2009) [24]
Bratislava,
Urban
0.0001
0.02
Meresova et al., (2008) [25]
Slovakia
Urban
Huelva, Spain
0.0006
0.02
Sanchez de la Campa et al., (2007) [26]
Edinburgh, UK
Urban background 0.0003
0.01
Heal et al., (2005)b [27]
Urban
Los Angeles, USA
NR
0.002
Singh et al., (2002) [28]
NR: not reported; BDL: below detection limit, a: sampling in March-April 2006, b: median values
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Table -2 show that various studies on Trace metals (lead and cadmium) level in PM10 samples
have been undertaken in different countries of the world.
Khillare and Sarkar (Khillare and Sarkar; 2012) reported the Pb concentration in particulate
matter in urban residential areas within the range 0.27 to 0.46 µg/m3. In the present study (table1) average concentration of lead in residential areas was recorded 0.92 µg/m3 which is higher
from Delhi, India (Shridhar et al; 2010), Coimbatore, India (Vijayanand et al., 2008), Beijing
China (Khan et al; 2010) and Tocopilla, Chile (Jorquera; 2009), in urban background areas was
recorded as 0.08 µg/m3, which is higher than that reported for urban background of Italy (Contini
et al., 2010) and UK (Heal et al; 2005). Level of lead and cadmium also analyzed in the samples
collected from industrial and commercial areas of Karachi city. The average concentration of
lead in industrial areas was found to be 1.21 µg/m3 whereas in commercial areas of Karachi was
found to be 1.36 µg/m3 respectively. Khillare and Sarkar (Khillare and Sarkar; 2012) also
reported the concentration of cadmium in particulate matter range from 0.01 to 0.02 µg/m3.
Table 1 shows that, in the present study the average concentration of Cd in residential areas was
recorded as 0.006 µg/m3 which is higher from Delhi, India (Shridhar et al; 2010), Coimbatore,
India (Vijayanand et al., 2008), Beijing China(Khan et al; 2010) and Tocopilla, Chile (Jorquera;
2009), in urban background areas was recorded as 0.003 µg/m3 which is higher than that
reported for urban background of Italy (Contini et al., 2010) and UK (Heal et al; 2005), in
industrial areas was found to be 0.009 µg/m3 whereas in commercial areas of Karachi was found
to be 0.008 µg/m3 respectively.
Table 3. Comparison of metal concentrations (µg m3) with USEPA and WHO guidelines
Pb
Cd
Commercial
(present study)
µg/m3
1.36
0.008
Residential
(present study)
µg/m3
0.92
0.006
Industrial
(present study)
µg/m3
1.21
0.009
U-background
(present study)
µg/m3
0.08
0.003
WHO
µg/m3
0.500
0.005
USEPA
µg/m3
1.500
0.006
In the atmospheric air toxic metals cannot be destroyed or shattered, and can be inhaled during
breathing. Various studies on atmospheric metal concentration and their health hazards have
been carried out in different cities of the world which shows variations in the concentration of
toxic elements like Lead and Cadmium (Freitas MC, et al; 2004). Both these toxic metals causes
12
different types of health hazards as slowing of heart rate, different types of cancer, Bronchitis
and leukemia (Khillare and Sarkar; 2012 and Jorquera; 2009). As lead is one of the well known
man made environmental pollutant and causes chronic obstructive pulmonary diseases, lungs
cancer, bronchitis and chief source of asthma both in young and older citizens. Even a very small
amount of lead exposure becomes physiologically active and results into its accumulation in the
food chain. Adverse health effects on humans particularly on infant Central Nervous System
(CNS) have been well established.
Cadmium is carcinogen to human body, inhalation of Cd, causing lung cancer, different types of
cardio-vascular diseases acute and chronic kidney diseases. Other effects due to cadmium
exposure due to breathing for a long time are lung damage and fragile bones (Järup L, Alfvén T;
2004).
In this study health risk by trace metals such as Pb and Cd were also investigated in the collected
samples of particulate matter. These investigated trace metals were found to be toxic at elevated
level and causing serious health hazards such as pulmonary diseases, cardiovascular diseases,
heart attacks, lungs infection, kidney diseases, loss of appetite, abdominal pain, dirrohea,
vomiting, blood pressure, constipation, paralysis and eye irritation respectively.
The following steps have been taken in this study.

Data has been collected by the ‘Questionnaire method’ covering various aspects of
environment like socio -economic status, outdoor air pollution, vehicular pollution,
industrial pollution, sanitation, quality of drinking water and diseases like respiratory,
gastrointestinal, eye diseases, skin problems, water/vector borne diseases, cancer,
cardiovascular and miscellaneous ones have been taken into consideration. Initially a
draft questionnaire was developed on issues such as socio-economic background of the
respondents about the health hazards of particulate air pollution (PAP).

Questionnaires has been filled from 350 respondents (150 from commercial, 76 from
residential, 100 from industrial and 24 from urban background areas) about their health
status.

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Percentages of the effectes were also calculated during the study.
Figure 6 a, b, c and d shows the % of health related diseases in selected areas as Commercial,
residential, industrial and urban background areas of Karachi.
14
Figure 6 a,b,c and d: Area Wise Percentage Health Hazards Related to Karachi’s Environment.
Figure 7 shows the overall % of health related diseases in in the environment of Karachi city.
The collected data from questionnaires filled by 350 respondents show that 11% had developed
cancer, 8.01% fatigue, 18.0% respiratory diseases, 7% skin disease, 10% headache, 16% heart
attack, 9% eye irritation, 7% allergy and 14% Asthma respectively in the concerned areas.
15
Figure 7:
Overall average % age of health hazard related to total environment of Karachi.
Result of this study shows that average health situation has close linkage with particulate matter
path ways and population. The infants, elders, and the persons who suffer with chronic
cardiopulmonary diseases, influenza or asthma are at the risk of mortality and serious morbidity
effects while others are vulnerable to less serious health effects such as increase in respiratory
diseases, decreased lung function or physiological changes.
Conclusion
Toxic trace metal contamination in urban areas of Karachi shows that growing number of
vehicles, leaded gasoline consumption and poor conditions of the roads are major cause of high
concentration of lead and other trace metals level in the environment of Karachi.
High concentrations of trace metals in atmospheric particulate matters are a great threat for the
public health in Karachi, Pakistan. Therefore, it is very important to determine the concentration
levels of trace metals as per WHO guidelines.
Lead and cadmium in particulate matter sample were measured in Karachi city. The average
cadmium concentration was slightly higher but very close to the WHO guideline value. The lead
16
concentration was below the USEPA values and slightly higher than WHO guideline value and
also showing decreasing tendency as compared to the previous measurements in Karachi.
The results from this study may be useful for assisting with calculating the planning and
regulation. A valuable control policy should be developed and implementation should be carried
out to avoid the trace metals in particulate pollution which is a major problem in the city.
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